(a) Technical Field
The present invention generally relates to a crossover conveyor chain system including a first conveyor chain and a second conveyor chain which crosses the first conveyor chain, and more particularly to a crossover conveyor chain system capable of transferring the product more smoothly and stably from the first to the second conveyor chain while reorienting the product to a direction nearly perpendicular to that on the first conveyor chain, and which is more simple in construction, robust and less expensive.
(b) Background Art
Heretofore, various crossover conveyor chain systems have been proposed. One typical example is known from the Japanese Unexamined Application Publication No. 239117 of 1996 which discloses a mechanism for reorienting a product being transferred from one of two conveyors laid to cross each other to the other. The reorienting mechanism for a product to be transferred from one conveyor chain to the other includes a means whose cantilever-shaped second portion, onto which the product to be transferred from the first to second conveyor is once transferred, is removably attachable to the lateral side of a link module.
Disadvantageously, however, the aforementioned means is complicated in construction and difficult to assemble. Also, even if the end of the cantilever-shaped second portion is designed to be at the same level as the top of the first conveyor for smooth transfer of the product, the cantilever-shaped second portion can hardly transfer the product smoothly because it is easily bendable at the portion thereof attached to the link module, and it tips up the link by its load of levering or gouges the product at the free end thereof.
Accordingly, the present invention has an object to overcome the above-mentioned drawbacks of the background art by providing a crossover conveyor chain system simple in construction, highly strong and rigid, lightweight, suitable for mass production, easy to assemble, easy to handle, and less expensive.
The above object can be attained by providing a crossover conveyor chain system in which the product is transferred from a first conveyor chain (S1) to a second conveyor chain (S2) while reorienting the product to a direction nearly perpendicular to that on the first conveyor chain (S1), wherein:
the first conveyor chain (S1) is formed to have an end thereof adjacent to the second conveyor chain (S2) circumrotatably supported on an end bar (10) having a rounded edge whose radius of curvature is smaller or on a small-diameter sprocket;
the second conveyor chain (S2) includes at least two types of chain units (A) different in length from each other, and a long coupling pin (B) which couples the chain units A to each other in the conveying direction as well as in the width direction of the conveyor chain (S2);
the chain unit (A) including a plurality of front convex portions (1) and a plurality of front concave portions (3), disposed alternately at the front thereof, and a plurality of rear convex portions (2) and a plurality of rear concave portions (4), disposed alternately at the back thereof, and a transfer overhanging portion (7) formed integrally at one lateral thereof; and
the transfer overhanging portion (7) having formed at the free end portion and at the bottom thereof a beveled surface (8) which is generally parallel to a trajectory delineated by the first conveyor chain (S1) when moving along the upper edge of the end bar (10) and also formed at the free end portion and at the top thereof an inclined surface (9) which gradually descends as it goes toward the outer end thereof.
In the above crossover conveyor chain system according to the present invention, since the transfer overhanging portion (7) positioned obliquely above an end, adjacent to the second conveyor chain (S2), of the first conveyor chain (S1) can be set to have a short length (overhang length), it can be formed not easy to flex and break. Thus, the transfer overhanging portion (7) can easily be improved in strength and durability. Thus, the moment developed to the chain unit (A) when a weight of the product is applied to the end of the transfer overhanging portion (7) can be minimized and the chain unit (A) itself will not possibly be lifted and inclined. Therefore, the product can be transferred smoothly without being overturned.
Since the transfer overhanging portion (7) having formed at the free end portion and at the bottom thereof a beveled surface (8) which is generally parallel to a trajectory delineated by the first conveyor chain (S1) when moving along the turn-around end thereof and also formed at the free end portion and at the top thereof an inclined surface (9) which gradually descends as it goes toward the outer end thereof, the beveled lower surface (8) permits the transfer overhanging portion (7) to easily be located nearer to the first conveyor chain (S1) and the upper inclined surface (9) permits to transfer the product more smoothly from the first conveyor chain (S1) to the second chain conveyor (S2).
Since the second conveyor chain (S2) includes at least two types of chain units (A) different in length from each other, and a long coupling pin (B) which couples the chain units A to each other in the conveying direction as well as in the width direction of the conveyor chain (S2) and the chain unit (A) has the plurality of front convex portions (1) and plurality of front concave portions (3), disposed alternately at the front thereof, and the plurality of rear convex portions (2) and plurality of rear concave portions (4), disposed alternately at the back thereof, the connections between the chain units (A) will not be in line with each other in the conveying direction and thus the load (weight) of the product on the conveyor chain will not easily concentrate on a limited portion of the conveyor chain and will be difficult to flex vertically under the weight of the product being transported.
In addition, since the transfer overhanging portion (7) is formed integrally with the chain unit (A), so it will have an improved strength, rigidity, durability, etc., which assures a stable transfer of any product which is relatively heavy. Also, the second conveyor chain (S2) itself can be simple in construction, suitable for mass production and less expansive.
Thus, according to the present invention, the crossover conveyor chain system is highly strong and rigid, easy to be designed lightweight and compact, simple in construction, suitable for mass production, easy to assemble, easy to handle, and less expensive.
In the crossover conveyor chain system according to the present invention, it is desirable that support rails (11) should be provided which can be located near the first conveyor chain (S1) and support at the top thereof the second conveyor chain (S2) at one of the lateral lower side and the chain unit (A) should have formed thereon a guide projection (6) which is in sliding contact with the other lateral side of the support rail (11). Also, the second conveyor chain (S2) is supported on a support rail (12) at the central bottom portion thereof and on another support rail (6) at the other lateral lower side thereof. The chain unit (A) has further guide projections (6) which are in sliding contact with the opposite lateral sides, respectively, of the support rail (11).
Because of the above construction of the crossover conveyor chain system, the second conveyor chain (S2) can stably be supported on the support rails (11) at the lateral sides thereof and on the support rail (12) at the central portion thereof. So, the chain unit (A) of the second conveyor chain (S2) can be prevented from being lifted and inclined.
In addition, the guide projections (6) prevent the second conveyor chain (S2) from being laterally deflected to positively prevent the second conveyor chain (S2) from touching the first conveyor chain (S1). Also, the guide projections (6) can maintain a small space between the second and first conveyor chains (S2 and S1).
Also, in the crossover conveyor chain system according to the present invention, the second conveyor chains (S2) should desirably be formed from the chain units (A) different in length from each other and alternately disposed in the conveying direction, whereby it is possible to positively prevent the width-directional connections between the chain units (A) in pair from being in line with each other, the load (weight) of the product on the conveyor chain from concentrating on a limited portion of the conveyor chain, and make the conveyor chain difficult to flex vertically under the weight of the product being transported.
In addition, in the crossover conveyor chain system according to the present invention, it is desirable that the front convex portion (1) or rear convex portion (2), contiguous to the transfer overhanging portion (7), of the chain unit (A) in the second conveyor chain (S2) should partially cut to be generally parallel with the trajectory delineated by the first conveyor chain (S1) when moving along the turn-around end thereof.
Because of the above construction, the front convex portion (1) or rear convex portion (2) contiguous to the transfer overhanging portion (7) can be located nearer to the end, adjacent to the second conveyor chain (S2), of the first conveyor chain (S1) and thus can be set to have a short length (overhang length). Therefore, the transfer overhanging portion (7) can be formed not easy to flex and break. Thus, the transfer overhanging portion (7) can be improved in strength and durability.
Further, the moment developed to the chain unit (A) when a weight of the product is applied to the end of the transfer overhanging portion (7) can be minimized so that the chain unit (A) will not possibly be lifted and inclined and thus the product can be transferred more stably and smoothly without being overturned.